Temple of Farts rather sounds to me like either some grossout comedy or a bizarre fetish video. (2girls1cup anyone? No, I've never seen it and I don't want to.)

But, to get back on topic... a direct translation of Alien Earth would be something like Le Terre Extraterestiel... it doesn't sound right. Or to go back to the Harry Potter example, it's probably the same reason that the US version was called Harry Potter and the Sorcerer's Stone: philosopher doesn't really imply magic, although one would expect readers to know what the philosopher's stone is... (In Dutch, the philosopher's stone is known as "de steen der wijzen": the stone of the wise.)

I understand what you're saying, but what bugs me the most in the Harry Potter case is that they are giving away one of the largest plots in the book with that title. That's what so nice about the first book; the entire discovery of Hogwarts. If you slap a title on there that already tells any potential readers what's going to happen, then that's pretty daft imo.

I'm not quite sure anyone ever went into Harry Potter without knowing that he's going to a wizards' school, even before the books become famous. It is stated openly on the back of both the English and Dutch editions in any case.